/*******************************************************************************
 * Copyright 2008 www.softao.com
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package com.softao.ming.gwt.user.client.util;

import com.softao.ming.gwt.user.client.InvalidPatternException;

/**
 */
public final class PatternReader {
	private final String mPattern;

	private int mPosition;

	/**
	 * Initializes a new instance of <code>PatternReader</code>.
	 * 
	 * @param pattern
	 *            pattern
	 */
	public PatternReader(String pattern) {
		this.mPattern = pattern;
		this.mPosition = -1;
	}

	/**
	 * @return <code>true</code> if there are more characters
	 */
	public final boolean hasMore() {
		return (this.mPosition + 1) < this.mPattern.length();
	}

	/**
	 * @return next character in the pattern
	 * @throws InvalidPatternException
	 */
	public final Character next() throws InvalidPatternException {
		this.mPosition++;
		if (this.mPosition >= this.mPattern.length()) {
			String msg = "Unexpected end of pattern reached";
			throw new InvalidPatternException(msg);
		}

		return this.mPattern.charAt(this.mPosition);
	}

	/**
	 * @return the pattern
	 */
	public final String getPattern() {
		return mPattern;
	}

	/**
	 * @return the position
	 */
	public final int getPosition() {
		return mPosition;
	}
}
